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Zafirlukast for asthma


Clinical author's note Michael Stewart 12/9/2018: Accolate® tablets were discontinued in the UK in March 2018. At the time of review there are no branded or generic products containing zafirlukast available in the UK. Zafirlukast may still be available in other countries. This medicine leaflet is based on medical information available in the UK at the time of writing and is left here for reference purposes. Please also refer to the manufacturer's information supplied with your medicine.

Take zafirlukast twice daily, one tablet in the morning and one in the evening.

Your doctor will prescribe a reliever inhaler for you to use in case you have an asthma attack. Make sure that you keep it with you all the time.

The most common side-effects are high temperature (fever) and frequent sore throats and infections.

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About zafirlukast

Type of medicine

A leukotriene receptor antagonist

Used for

Asthma (for adults and for children aged over 12 years)

Also called


Available as


Asthma is a common condition caused by inflammation in the smaller airways of the lungs. The inflammation irritates the muscles around the airways and causes them to constrict. This causes your airways to narrow. It is then more difficult for air to get in and out of your lungs. This causes the typical symptoms of wheeze, chest tightness and shortness of breath. The inflammation also causes the lining of your airways to make extra mucus which causes coughing.

Asthma symptoms can flare up from time to time and there may be no apparent reason why. However, some people find that symptoms are made worse by triggers such as exercise and pollen. These things cause your body to produce chemical substances called leukotrienes, which cause the inflammation. Zafirlukast helps control the symptoms of asthma by blocking the effects of these leukotrienes.

Before taking zafirlukast

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking zafirlukast it is important that your doctor knows:

  • If you are pregnant, trying for a baby or breastfeeding.

  • If you have any problems with the way your liver works, or any problems with the way your kidneys work.

  • If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

  • If you have ever had an allergic reaction to a medicine.

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How to take zafirlukast

  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about zafirlukast and will provide you with a full list of the side-effects which you could experience from taking it.

  • Take zafirlukast exactly as your doctor tells you to. The usual dose is one tablet in the morning and one in the evening.

  • Swallow the tablet with a drink of water. You should take it 'on an empty stomach', which means that you should take the tablet about an hour before a meal, or wait until two hours afterwards. This is because your body absorbs less zafirlukast after a meal, which means the medicine is less effective.

  • Take zafirlukast regularly every day, even if your asthma is well controlled. Try not to miss any of your doses but if you do forget, take it as soon as you remember. If when you remember, it is almost time to take your next dose then skip the missed dose and take your next dose when it is due. Do not take two doses together to make up for a forgotten dose.

Getting the most from your treatment

  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. Also, your doctor may want you to have blood tests from time to time to check on the way your liver is working.

  • Zafirlukast will not give you immediate relief if you are having an asthma attack. Your doctor will prescribe a reliever inhaler for you to use if this happens. Make sure that you keep it with you all the time in case you need to use it.

  • If you find that your asthma symptoms are getting worse, or that you need to use the reliever inhaler more regularly than usual, please contact your doctor or nurse for advice straightaway.

  • Do not smoke. Smoking causes severe irritation and damage to the lungs. It will make your condition worse and will reduce the beneficial effects of your medication.

  • If you buy any medicines, check with a pharmacist that they are suitable for you to take. Some anti-inflammatory painkillers and aspirin can make asthma symptoms worse in some people.

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Can zafirlukast cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains the most common ones associated with zafirlukast. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Very common zafirlukast side-effects (these affect more than 1 in 10 people)

What can I do if I experience this?

High temperature (fever), sore throat and chest infections

If troublesome, speak with your doctor

Common zafirlukast side-effects (these affect fewer than 1 in 10 people)

What can I do if I experience this?

Feeling sick (nausea) or being sick (vomiting), tummy (abdominal) pain

Stick to simple meals and drink plenty of water. Speak with your doctor if this continues

Headache, muscle aches and pains

Ask your pharmacist to recommend a suitable painkiller if troublesome

Important: if you get any of the following symptoms, you should let your doctor know straightaway so that you can have a check-up:

  • Constantly feeling or being sick, stomach pain, yellowing of your skin or the whites of your eyes (jaundice) and feeling generally unwell. These can be signs of a problem with your liver.

  • Flu-like symptoms, tingling feelings or numbness in your arms or legs, difficulties with breathing, and skin rash. These can be a sign of a very rare but serious disorder called Churg-Strauss syndrome.

If you experience any other symptoms which you think may be due to the tablets, please speak with your doctor or pharmacist for further advice.

How to store zafirlukast

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have had an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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